Fear of predators alters herbivore regulation of soil microbial community function

Fear of predation can affect important ecosystem processes by altering the prey traits' expression that, in turn, regulates the quantity and quality of nutritional inputs to soil. Here, we aimed to assist in bridging a knowledge gap in this cascading chain of events by exploring how risk of spider predation may affect grasshopper prey performances, and the activity of various microbial extracellular enzymes in the soil. Using a mesocosms field‐experiment, we found that grasshoppers threatened by spider predation ate less, grew slower, and had a higher body carbon to nitrogen ratio. Herbivory increased activity of all microbial extracellular enzymes examined, likely due to higher availability of root exudates. Predation risk had no effect on C‐acquiring enzymes but decreased activity of P‐acquiring enzymes. We found contrasting results regarding the effect of predation on the activity of N‐acetyl‐glucosaminidase and leucine arylamidase N‐acquiring enzymes, suggesting that predation risk ..., Site description and experiment design We conducted our field experiment at Jilin Songnen Grassland Ecosystem National Observation and Research Station, Changling, China (44°45′ N, 123°45′ E). The climate in this site is semi‐arid continental and monsoon with average annual precipitation ranging from 280 to 400 mm. This system is dominated by the grass L. chinensis, and its main insect herbivore E. unicolor grasshopper. Wolf spiders are common predators of grasshoppers in this system. We tested how the risk of spider predation regulates grasshoppers' trophic function and subsequently soil microorganism enzymatic activity and stoichiometry, by setting a randomized block experiment with three‐trophic‐level treatments: (i) plants (control), (ii) plants and grasshoppers (herbivore), and (iii) plants, grasshoppers, and spiders (predation risk; Figure 1). We constructed 10 blocks of three 0.25‐m2‐basal area, 0.9‐m‐high mesocosms covered by 0.8 mm × 1.2 mm mesh size screen. All mesocosms were ...,捕食恐惧可通过改变猎物性状表达，进而调控输入土壤的营养物质的数量与质量，从而影响关键生态系统过程。本研究旨在填补这一链式级联效应研究中的知识空白，探讨蜘蛛捕食风险如何影响猎物（蝗虫）的生长表现，以及土壤中各类微生物胞外酶的活性。基于中型实验生态系统（mesocosms）的野外实验结果显示：受蜘蛛捕食威胁的蝗虫取食量下降、生长速率减缓，且体碳氮比升高。植食作用提升了所有被测微生物胞外酶的活性，这可能源于根系分泌物的可利用性升高。捕食风险对碳获取酶活性无显著影响，但会降低磷获取酶的活性。针对捕食对氮获取酶（N-乙酰氨基葡萄糖苷酶与亮氨酸芳基酰胺酶）活性的影响，本研究得到了相悖的结果，表明捕食风险…… 研究地点与实验设计 本野外实验在中国吉林松嫩草原生态系统国家野外科学观测研究站（位于吉林省长岭县，坐标44°45′N，123°45′E）开展。该区域气候为半干旱大陆性季风气候，年均降水量介于280~400毫米之间。该生态系统的优势植物为羊草（Leymus chinensis，缩写L. chinensis），主要昆虫植食者为雏蝗（Euthalobia unicolor，缩写E. unicolor），该生境内狼蛛是蝗虫的常见捕食者。 本研究设置了三营养水平的随机区组实验，以探究蜘蛛捕食风险如何调控蝗虫的营养功能，进而影响土壤微生物酶活性与化学计量比，实验设置如下3种处理：（i）植物组（对照组）；（ii）植物+蝗虫组（植食组）；（iii）植物+蝗虫+蜘蛛组（捕食风险组；图1）。我们构建了10个区组，每个区组包含3个底面积0.25平方米、高度0.9米的中型实验生态系统，装置外覆孔径为0.8mm×1.2mm的网纱。所有中型实验生态系统均……